Air conditioning system



Nov. 19, 1940.

L.AL PFHLJPF AIR CONDITIONING SYSTEM Filed Nov. 8, 1955 1w CINTOR.

MW/554m: 4. P/l/L/PP WMMM ATTOR EX Patented Nov. 19, 1940 UNITED STATES .azzazas; AIR CONDITIONING SYSTEM Lawrence A. Philipp. Detroit, Mich., assignor, by

mesne assignments, to Nash-Kelvinator Corporation, Detroit, Mich., a corporation of Maryland Application November 3,1933, serial No. 697,171

6 Claims.

llhe present invention relates to the art of conditioning air and particularly to the method of and apparatus for cooling and dehumidifying air. One of the objects of the present, invention is to provide an improved method of and apparatus for conditioning air by which method and apparatus, the air to be conditioned is circulated in heat exchange relation with the heat absorbing I element to cool and dehumidify the air, control the flow of refrigerating medium through the heat absorbing element so as to maintain the air between high and low temperature limits normally desirable for comfort and in case of an undesirable humidity under these temperature conditions, to modify the flow of refrigerating medium through the element, and to limit. such modified operation so that the modified temperature is not extended beyond an uncomfortable state.

Other and further objects and advantages will be apparent from the following disclosure, reference being had to the accompanying drawing wherein a preferred form of embodiment of the present invention is clearly shown.

In the drawing:

The figure illustrates diagrammatically my improved air conditioning system as applied for cooling a room. Referring to the drawing, the numeral indicates a side wall and the numeral it indicates the floor of a room in which the air therein is to be conditioned. In the present illus 1 tration the conditioning apparatus isdisposed in till till

the room'and comprises a cabinet '23Ihavingan air inlet opening 24 and an air outlet opening A drain pipe 22 conducts water to the'exterior of the cabinet. Air is circulated through the cabinet 23 by a fan 25 which is driven by a motor 21. Any type of controllable heat absorbing element may be used in the present invention and I have chosen for illustrating purposes an evaporator 23 of a mechanical refrigerating system. This evaporator includes a series of pipes which are provided with fins 3! for increasing the heat conductingsurface thereof. Any type of valve may be used for controlling the flow of refrigerating medium to the evaporator 29 and in the present instance I have shown a valve which'is known in the art as a thermostatic expansion valve 33. This valve is opened in response to a decrease in pressure in the evaporator and closes when the pressure in the evaporator attains a predetermined high value but which is modified by a thermostat including a bulb 34 connected by a pipe to the valve. This bulb is responsive to the temperature of the outlet of the evaporator and is arranged to close the valve-33 when vaporization of liquid refrigerant takes place at the outlet of the evaporator. The bulb 34 is shown connected to the outlet pipe 35 which leads to the low pressure side oia compressor 31. The high a pressure operated snap I completed from wire 43 pressure side of the compressor 31 is connected by a'pipe 38 to a condenser 38 and the condensed refrigerant flows from the condenser 39 into a receiver 40. The pipe 42 conducts liquid refrigerant Irom the receiver 40 to the expansion valve 33.

The compressor is driven by a motor l3 by means of a belt 44. y I

When the compressor operates it will withdraw the gaseous refrigerant. from the evaporator 29 through the pipe 36, compress the refrigerant and force the same into the condenser 39 where it is cooled and liquefied and flows into the receiver 40 where it is conducted by the pipe 42 to the expansion valve 33.

The circuit to the motor comprises wire #6 contacts 41 and 48 of a magnetic switch t9, wire 50, motor .43 and wire 5!. Contact 41 is movable and is actuated by a magnet coil 53.

Air passing through the cabinet 23 and over the evaporator 23 will be cooled. It is desirable to maintain the air within predetermined high and low temperature limits and therefore the heat exchange between the air and the evaporator must be controlled. In the present embodiment of the invention, the heat exchange is controlled by controlling the temperature of the evaporator 29 and this is accomplished by starting the compressor when a predetermined high "temperature is obtained and stopping the compressor when a predetermined low temperature is obtained. It is well understood that a comfortable temperature varies with the relative humidity of the air. 7 For example a temperature of 83 F. of the air at 50% relative humidity is considered a comfortable temperature. In accordance with the present invention I desire to maintain the air between 82 F. and 84 F. and for this purpose I provide a thermostat 55 which is connected by-a tube 561:0 switch 51. This switch 51 is 'arranged to close its contacts when the temperature oi the air contains 84 I and open its contacts when the temperature is decreased to 82 due .to the expansion and contraction of a volatile fluid contained within-thermostat 55 and tube 55. When the temperature of the air is above 84 F. a circuit is through wires 59 and 60, snap switch 51, wire 6 l wire 32, through the contacts of a snap switch 63, which is normally closed ,at this time as will be hereinafter explained, magnet coil 53 and wire 64 hich is connected to the main 5i. When this the coil-53 is energized causing the movable contact to engage contact it and thereby complete the circuit to motor 53. This will cause the compressor to be driven to reduce the temperature of evaporator 29 and when the temperature of'the air is reduced to 82 the circuit to the magnet coil 53 will be interrupted to thereby stop the operation of the motor 43 and compressor 31.

circuit is completed I The humidity of the air in the room changes due to changes in the environment and due to the direct adding of moisture to the air and if the relative humidity of the air is high, a mean temperature of the air at 83 F. will be uncomfortable. In order to rectify this condition, I provide for cooling the air to a lower temperature and for this purpose I provide an instrument, preferably a humidostat 66 which is connected in parallel'circuit relation with snap switch through wires 61 and 68. When the relative humidity is too high the humidostat closes its contacts and completes the circuit to the magnet coil 53 as follows; main 46, wires 59 and 61, humidostat 66, wires 68 and 62, snap switch 63, coil 53 and wire 64 to the main 5|. It will be apparent therefore that although the temperature of the air is below 82 F. and the snap switch 51 is open, a circuit is completed nevertheless through magnet coil 53 to maintain the motor operating. This operation of course will cause a prolonged operation of the compressor 31 and likewise a reduction in temperature of the evaporator 29 whereby more moisture will be removed from the air due to its condensation on the evaporator.

Under some conditions the relative humidity may be such that the compressor would operate long enough to reduce the temperature of the air to such degree as to provide an uncomfortable low temperature and in order to prevent such a condition, I provide for stopping the compressor when the temperature of the air attains a predetermined low value below which the air would be uncomfortable. For this purpose I provide a thermostat which is connected to the pressure operated snap switch 63 by a pipe N. This system H and 63 contains a volatile fluid which is arranged to expand and contract in response to changes in temperature. When the temperature of the air in the room is decreased, for example, to 76 F., the pressure in thermostat Hi is decreased suflicient to actuate the snap switch 83 to cause its contacts to be separated, therefore regardless of whether there is a demand for further dehumidification through the agency of the humidostat 66, the circuit through humidostat 66 will be broken by snap switch 63 to stop the motor 43 and compressor 31.

Thus it is apparent that I have provided an air conditioning system which maintains a comfortable temperature under proper humidity conditions and in case of uncomfortable humidity conditions, I provide for the further removal of moisture from th4a air by further cooling of the air, but such further cooling is limited so that the air does not become too cold for comfort.

While the form of mechanism herein shown and described constitutes a preferred embodiment of my invention, it is to be understood that other forms may be adopted all coming within the scope of the following claims:

I claim:

1. An air conditioning system comprising in combination, a refrigerating apparatus including heat absorbing means about which the air which is to be conditioned is circulated, means for causing refrigerating medium to flow through said heat absorbing means for maintaining the air between predetermined temperature limits, means for changing one of said temperature limits, said last means being responsive to an undesirable humidity condition of the air for controlling the refrigerating apparatus, and means responsive to a predetermined modified limit of temperature for controlling the refrigerating apparatus.

2. An air conditioning system comprising in combination, a refrigerating apparatus including heat absorbing means about which the air which is to be conditioned is circulated, means for causing refrigerating medium to flow through said heat absorbing means for maintaining the air between predetermined temperature limits, means for modifying the operation of the refrigerating apparatus for obtaining a lower temperature of the air, said last means being responsive to a relatively high humidity condition of the air, and means responsive to a predetermined modified low limit of temperature for controlling the refrigerating apparatus.

3. An air conditioning system comprising in combination, a refrigerating apparatus including heat absorbing means about which air which is to be conditioned is circulated, means for cyclically causing refrigerating medium to flow through said heat absorbing means, means responsive toa predetermined high temperature limit and to a predetermined low temperature limit of theair to be conditioned for starting and stopping the second named means, means for modifying the operation of the second named means for changing one of the temperature limits, said means being responsive to an incorrect humidity condition, and means responsive to a predetermined modified limit of temperature for controlling the second named means.

4. An air conditioning system comprising in combination, a refrigerating apparatus including heat absorbing means about which air which is to'be conditioned is circulated, means for cyclically causing refrigerating medium to flow through said heat absorbing means, means responsive to a predetermined high temperature limit and to a predetermined low temperature limit of the air to be conditioned for starting and stopping the second named means, means for modifying the operation of the temperature responsive means for changing one of the temperature limits, said means being responsive to an incorrect humidity condition, and means responsive to a predetermined modified limit of temperature for controlling the second named means.

5. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a heat absorbing element, controlling the flow of refrigerating medium through the heat absorbing element to maintain the air between predetermined high and low temperature limits, modifying the flow of refrigerating medium through the element in response to an incorrect humidity condition of the air to be conditioned, and limiting such modified operation in accordance with the temperature of the air to be conditioned.

6. The process of cooling and dehumidifying air which comprises causing the air which is to be conditioned to circulate in heat exchange relation with a heat absorbing element, controlling the flow of refrigerating medium through the heat absorbing element to maintain the air between predetermined high and low temperature limits, increasing the flow of refrigerating medium through the element inresponse to a relatively high humidity condition of the air to be conditioned, and limiting such increased flow in accordance with the temperature of the air to be conditioned.

LAWRENCE A. PHILIPP.

CERTIFICATE OF CORRECTION, Patent No., 2,222,258e November 19, 191w,

LAWRENCE A, PHILIPP.

It is hereby certified that error appears in the printed specification of the above numbered patent q iring correction as follows: Page 1, second column, line 141, for the word "contains" read --attains--; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of January, A, D, 19L .l..

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

